Process of removing the impurities of raw sugar



(No Model.)

0. MATT'HIESSBN. PROCESS OP REMOVING THB'IMPURTIES 0F RAW SUGAR.

Patented Oct. 27, 1885..

, UNITED STATES PATENT OFFICE rnnrz'o. MATTHIEssEN, or I RVINGTON, NEW YORK.

PROCESS-OF REMOVING THE IMPURTIES OF RAW. SUGAR.

SPECIFICATION forming part of Letters Patent No. 329,331, dated October 27, 1885.

I A Application illed'Jnly 3, 1885. Serial No. 170,597. (No model.)

To all 107mm, it may concern.'

Be it known that I, FRANZ O. MATTHIEssEN, of Irvington, New York, have invented certain Improvements in Processes of and Apparatus for Removing the Impurities from Raw Sugar, of which the following is aspecification.

In certain processes of manufacturing refined cane-sugar heretofore practiced the raw sugar is first washed, by which some of its im purities are removed, and is then dissolved in water and filtered through bag-filters, by which other impurities are removed preparatory to the filtration of the sugar solution through bone -black. The sirup resulting from the washing of one lot o1' raw sugar is sometimes repeatedly used for mixing with other lots of `raw sugar-to .prepare them .for washingas described in Letters Patent of the United States No. 19l,539,issued to Franz O. Matthiesscn, June 5, 1877, according to which the sirup is used over and over forA mixing with raw Sugar until it becomes so charged with impurities that it ceases to be useful for that purpose. Some raw sugars of high grade contain so small a proportion of impurities that they do not require to be washed, but may at once be dissolved in water and filtered through filter-bags for the removal of their mechanical impurities preparatory to filtration through bone-black. By the present invention, in the process of refining raw sugar, the preliminary filtration through bag-filters is dispensed with, and the mechanical impurities are removed from the raw sugar ny mechanical means in connection with the bone-black filter itself, and while the process of .filtration ,through boncblack is being continuously carried on. The process embraces the vfollowing steps: First, the raw sugar, if of los grade, is washed to remove a portion of its impurities; secondly, the washed sugar is dissolved in water, or, if of high grade, the raw sugar is dissolved in water wit-hout having been previously washed. -N ext, the sugar solution obtained in either of these ways, instead of being filtered through bag-filters, is at once filtered through bone-black by the process of upward tilt-ration' through a column of boneblack contained in a filtering-chamber provided at the bottom with a scraper ordischarger for removingthe successive strata from the base of the columnA with which the sugar solution first acquires contact as rapidly as may be required by the exhaust-ion of the deeolorizing power of the bottom stratum and the presenceof mechanical and other impurities which may collect at that point.

Any suitable apparatus' may be employed for washing the raw sugar-such as, for ex ample, that described in Letters Patent of the United States No. 303,443, dated August 12, 1884` granted to F. O. Matthiessen and George Dinkel. Starting with araw sugar from which a portion of the impurities has been removed by washing, or with a raw sugar containing only a moderate proportion of impurities, which, therefore, has not needed washing, the raw sugar is dissolved in wat-er, forming a solution of, say, 30 Baume, and then filtered upwardly through bone-black contained in a filtering-chamber provided at the bottom with a scraper or other instrumentality, which, by its operation while the process of filtration is being continuously carried on, grada/ally removes the exhausted boue-black au'd 't e iinpurities which collect a'. il.; 1mice wh re the sugar solution is iirst brought -ato contact with the bone black. The sirup resulting i'vom the washing of the raw sugar may also be diluted with water and filtered in the same way. The speed with which the scraper or other discharging instrumentality is operated for theremoval of the impurities and exhausted bone-black from the iiltcring-ehamber will of eoursebe varied according to the quantity, and also according to the character ol` the impurities present in the solution which is to be iltered. Y Y

Among the mechanical impurities present in raw sugar are sand, clay, and sometimes liber. A certain portion of them having, when necessary, been removed by washing the raw sugar, the remainder is removed by the boneblack, and is collected with the exhausted bone-black discharged by the scraper Ior discharger from the surface of the mass oif boneblack with which the sugar solution is first brought intocontact. ties contained in the sirups produced by washing the raw sugar are removed by diluting the sirup and filtering it through a. bone-black filter provided with a scraper or discharger,

Similarly the impuriand it therefore results that the impurities from the raw sugar are concentrated in a comparatively small quantity of bone-black- -that is, the exhausted bone-black which is removed from time to time or continuously by the operation of the discharging instrumentality.

By means of' the improved apparatus forming part of the present invention provision vis made for carrying on a`continuous decolorzing operation, in which all the sugar-liquor which is forced through .the filtering-cl-iamber is subjected to uniform conditions with respect to the fixed quantity of bonehlack, the decolorizing power of which is maintained substantially unchanged by the gradual removal of the exhausted bouc-black and collected impurities from the bottom of the filtering-chamber and thev concurrent feeding of fresh bone-black into the top ofthe filtering chamber.

In its essential features the apparatus consists of, first; a filtering-chamber into the top of which the fresh bone-black is fed as required; secondly, a supporter and dischargcr or scraper for supporting the column ofboneblack contained in the filtering-chamber, and for effecting at a prescribed rate the gradual removal of hone-black from column as the bone-black at that point becomes exhausted and charged with impurities separated from the sugar-liquor which enters the filtering-chamber at the bottom; thirdly, a receiving-chamber beneath the filteringchamber for receiving the exhausted boneblack and collected impurities discharged from the filtering-chamber; fourthly, means for removing the exhausted bone-black and collected impurities from the receiving-chamber; and, finally, a conduit 'for introducing into the receiving-chamber under suitable pressure the sugar-liquor which is to be decolorized, and an outlet or outlets for the discharge from the upper part of the filteringchanlber of the sugar-liquor which has been forced upward through so much of the column of boneblack as is below the level ot' the said outlet or outlets.

The supporter and discharger constitutes the movable bottom of the filtering-chamber, and is a diaphragm provided with perforatons or slots of such shape and dimensions that while they will not permit the superincumbent bone-black to fall through them continuously under the influence merely of its own gravity, they will serve, when .the diaphragm is appropriately moved, to e'ect the removal and discharge from the base of the column of a stratum of bone-black o f prescribed thickness. 1

i Theaccompanyingdrawings,illustratingthc said improved apparatus, are as follows:

Figure 1 is a central vertical section of the filter iig-chamber, the receiving-chamber, and other appurtenances of the apparatus. Fig.

\ 2 is a horizontal section taken through theline duration of its contact with athe base of thev :rx on Fig. l, affordinga top viewof thc movable diaphragm. which eonstitntcsthe movable bottom of'thefiltering-clnnnbei, and whilh by reason of its functions is herein calledthe supporter and discharger or scrapcrJ Fig. 3 is a vertical section of the scraper, taken through the line y y on Fig. 2.

'The apparatus represented in the drziwings consists, substantially, of avertical cylinder, A, for containing a column of hone-black, 13, a movable slotted diaphragm or scraper, C, and a receiving-chamber, l), having an inclined bottom, D', by means of which the exhausted bone black and impurities removed by the scraper are conduct-ed by their own gravity into the bottom ofthe well E, from which theyA are elevated by means of the bucket-and chain elevator E', and are discharged at the mouth of the well upon the inclined chute E". The saccharine liquor to be decolorzed is introduced into the well by means of' the pipe F from asuitably elevated reservoir. r[he sugarliquor thus introduced falls into the bottom of the well, and rises by hydrostatic pressure through the mass of bone-black, B, contained in the filtering-chamber, and escapes therefrom through the perforations G in the side wall of the cylinder A into the externaltrough, G', from which` it is conducted to a suitable depository by .the discharge-pipe G2. The scraper C is circular, and is of larger diameter tha-n the cylinder A, so that its rim C is contained within the circumferential enlargement- A.' of' the cylinder A. The rim C. is supported upon the conical rollers H H, &c., which are provided with suitable bearings in standards erected within the enlargementof' the cylinder A. The scraper "s aixed to the vertical shaft I, t-helower end of which is provided with a bearing arranged upon the horizontal beam 1', having its central portion supported by the inclined braces I2 and I3. rlhe shaft I is provided with a bearing, t', at the top of the cyinder A, and has affixed to its upper end a driving-pulley or toothed wheel, i', to which power is applied to rotate the scraper. The scraperis provided with radially-slotted openings C" G, 82o. The upper edges, c and c', of' the side walls of each of' the slots G1' form, respectively, the one an acute and the other an obtuse angle with-the uppersurfaee of the diaphragm, substantially as shown in Fig. 3. The acute edge c is the cutting-edge, and, being somewhat higher than the obtuse angle c', operates, when the scraper is rotated, to cut away from the base ot' the column `of bonehlack a helical chip or shaving of uniform thickness, which falls down the inclined bottorn D of the receiving-chamberI) to the bottom of the well E, and is caught and carried upward by the buckets c e, &c. 'lhe buckets c e, &c. are made of wire-gauze, or are finely perforated, andthe well-tube is prolonged considerably above the level ol' the mouth of' the inlet-pipe F, in order that the sugar-liquor may have an opportunity to drain out ot flo IIO A I." l i i i buckets during the latter part of their upward hination, as herein set fort-h, `of a' filteringjourney before they discharge their contents chamber having a movable bottom for supupon the chute E. porting the column of bone-black Contained 2o What is claimed as the invention is in the filtering-chamber, and for gradually re- 5 1. Theherein-described process of removing moving the bone-black. from .the bottom of the impurities from raw sugar, the same consaid column, a receiving-chamber for recel; sisting in dissolving the raw sugar in water, ling the bone-black so removed from thelilte-rthen filtering it by forcing it. upward through ingehamher, and means for removing the 25 bone-black, and by means of aseraper ordisbone-blaclc from the receiviiig-chamber with` Io charger gradually removing the collected imont interrnptingthe upward flowof the sugarpurities and exhausted boue-black from the liquor through the column of bone-black to bottom of the mass of bone-blackV contained outlets provided t'or its exit-'from the filtert-1 in the filtering-chamber through which the chamber. Y sugar-liquor is forced. F. O. MATT]IIESSEi,v

15 2. In apparatus for effecting the decolori- Witnesses:

zation of sugar-liquor by the process of up- M. L. ADAMS,

.Ward filtration through bone-black, the com R. HCWES. 

